A high power electronic device package constructed to include a high power electronic device having an epitaxial surface attached to a thermally conductive submount by a thermally conductive interface layer having a eutectic metal contact therein. A gallium nitride high electron mobility transistor (GaN HEMT) having a transistor structure formed of a GaN thin film layer bonded to a thermally conductive host substrate via a thermally conductive interface layer disposed therebetween, and a method of forming the GaN HEMT. The GaN HEMTs can be used in such applications as, for example, power amplifiers with x-band radio frequency (RF) power outputs for micro-radar applications.
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1. A method of packaging a high-power electronic device, comprising: applying a first thermally conductive bonding material (TCBM) layer to an upper surface of a thermally conductive submount; disposing a metal frame and a diamond head upon the first TCBM layer; bonding the metal frame and the diamond head to the thermally conductive submount; disposing a second TCBM layer upon the metal frame and the diamond head; forming at least one via in the second TCBM layer; applying a eutectic metal in the at least one via to form at least one eutectic metal contact therein; disposing on the second TCBM layer the high-power electronic device having an epitaxial surface so that the epitaxial surface is in contact with the at least one eutectic metal contact; and securing the high-power electronic device to the at least one eutectic metal contact and to the thermally conductive submount to form a high-power electronic device package.
A method for packaging a high-power electronic device involves applying a thermally conductive bonding material to a thermally conductive submount, then placing a metal frame and a diamond heat spreader on top of the bonding material and securing them. A second layer of thermally conductive bonding material is applied over the frame and heat spreader. Vias are created in this second layer and filled with a eutectic metal to form electrical and thermal contacts. The high-power electronic device, which has an epitaxial surface, is then positioned so this surface contacts the eutectic metal. Finally, the device is secured to the eutectic metal contacts and the submount to create a complete high-power device package.
2. The method of claim 1 , further comprising: applying a first eutectic metal bonding layer to a second surface of the high-power electronic device; and bonding a ground plate to the second surface of the high-power electronic device via the first eutectic metal bonding layer.
Building upon the high-power electronic device packaging method where a thermally conductive submount is coated with a thermally conductive bonding material, a metal frame and diamond heat spreader are attached, a second bonding layer with eutectic metal-filled vias is added, and the high-power device is attached via those vias, this improved method also includes applying a eutectic metal bonding layer to the *backside* of the high-power electronic device. A ground plate is then bonded to the back of the device using this eutectic metal layer, enhancing electrical grounding and heat dissipation.
3. The method of claim 2 , further comprising: applying a second eutectic metal bonding layer to an exposed surface of the ground plate; and bonding a heat sink to the exposed surface of the ground plate via the second eutectic metal bonding layer.
Further expanding the method for packaging a high-power electronic device which includes a thermally conductive submount, a metal frame with diamond heat spreader, eutectic metal contacts, a high-power device attached via those contacts, and a ground plate attached to the device backside with eutectic metal; this version goes a step further. A second eutectic metal bonding layer is applied to the exposed surface of the ground plate. A heat sink is then bonded to this exposed surface using the second eutectic metal layer, providing additional cooling for the package.
4. The method of claim 1 , further comprising: applying a third TCBM layer to a lower surface of the thermally conductive submount; and bonding a heat sink to the lower surface of the thermally conductive submount via the third TCBM layer.
Following the packaging of a high-power electronic device using a thermally conductive submount, a metal frame with diamond heat spreader, eutectic metal contacts, and device attachment; this improved method adds a third layer of thermally conductive bonding material to the *bottom* surface of the thermally conductive submount. A heat sink is then bonded to this bottom surface using the third layer, enabling heat dissipation from the bottom of the package.
5. The method of claim 1 , further comprising: applying a first eutectic metal bonding layer to a second surface of the high-power electronic device; bonding a ground plate to the second surface of the high-power electronic device via the first eutectic metal bonding layer; applying a second eutectic metal bonding layer to an exposed surface of the ground plate; and bonding a heat sink to the exposed surface of the ground plate via the second eutectic metal bonding layer.
This packaging method builds upon the base method of attaching a high-power electronic device to a thermally conductive submount via eutectic metal contacts, and adds layers for improved heat dissipation. Specifically, a eutectic metal bonding layer is applied to the backside of the high-power electronic device, and a ground plate is attached. Then, a second eutectic metal bonding layer is applied to the ground plate's exposed surface, and a heat sink is attached to that surface to provide direct cooling.
6. The method of claim 1 , further comprising: applying a first eutectic metal bonding layer to a second surface of the high-power electronic device; bonding a ground plate to the second surface of the high-power electronic device via the first eutectic metal bonding layer; applying a second eutectic metal bonding layer to an exposed surface of the ground plate; and bonding a first heat sink to the exposed surface of the ground plate via the second eutectic metal bonding layer; applying a third TCBM layer to a lower surface of the thermally conductive submount; and bonding a second heat sink to the lower surface of the thermally conductive submount via the third TCBM layer to form a bilateral heat sink and high-power electronic device package.
This packaging method is an extension of the high-power electronic device packaging using thermally conductive submount, metal frame, diamond heat spreader, eutectic metal contacts, high-power device attachment and ground plate with heat sink. It applies a second heat sink to the bottom side of the device package. A third thermally conductive bonding material layer is applied to the bottom surface of the thermally conductive submount. A second heat sink is then bonded to the submount via the third thermally conductive bonding material layer, forming a bilateral heat sink configuration for enhanced cooling.
7. The method of claim 1 , wherein the high-power electronic device is a transistor, a high-electron-mobility transistor (HEMT), or a monolithic microwave integrated circuit (MMIC).
In the method of packaging a high-power electronic device using a thermally conductive submount, metal frame, diamond heat spreader, eutectic metal contacts, and high-power device attachment, the high-power electronic device is one of the following: a transistor, a high-electron-mobility transistor (HEMT), or a monolithic microwave integrated circuit (MMIC). Therefore, the method is suitable for packaging these specific types of electronic devices.
8. The method of claim 7 , wherein the HEMT comprises gallium nitride (GaN).
In the method of packaging a high-power electronic device using a thermally conductive submount, metal frame, diamond heat spreader, eutectic metal contacts, and high-power device attachment, where the high-power electronic device is a high-electron-mobility transistor (HEMT), the HEMT is made of gallium nitride (GaN). This indicates that the packaging method is specifically designed or suitable for GaN-based HEMTs.
9. The method of claim 1 , wherein the high-power electronic device comprises an epitaxial gallium nitride (GaN) layer structure comprising: a growth substrate comprising an epitaxial CaF 2 layer formed on an upper surface of the growth substrate; an epitaxial IV-VI semiconductor layer disposed on the epitaxial CaF 2 layer; a BaF 2 release layer disposed on the epitaxial IV-VI semiconductor layer; and an epitaxial GaN layer disposed on the BaF 2 release layer.
Within the method of packaging a high-power electronic device using a thermally conductive submount, metal frame, diamond heat spreader, eutectic metal contacts, and high-power device attachment, the high-power electronic device has an epitaxial gallium nitride (GaN) layer structure. This structure includes a growth substrate with an epitaxial CaF2 layer, an epitaxial IV-VI semiconductor layer on the CaF2, a BaF2 release layer on the IV-VI semiconductor, and an epitaxial GaN layer on the BaF2 release layer. This describes a specific GaN layer architecture suitable for use with this packaging technique.
10. The method of claim 9 , further comprising removing the growth substrate by dissolution of the BaF 2 release layer.
In the method of packaging a high-power electronic device with an epitaxial gallium nitride (GaN) layer structure that includes a growth substrate comprising an epitaxial CaF2 layer formed on an upper surface of the growth substrate; an epitaxial IV-VI semiconductor layer disposed on the epitaxial CaF2 layer; a BaF2 release layer disposed on the epitaxial IV-VI semiconductor layer; and an epitaxial GaN layer disposed on the BaF2 release layer; the growth substrate is removed by dissolving the BaF2 release layer.
11. The method of claim 1 , wherein the first TCBM layer comprises a first phase material and a second phase material, wherein the first phase material comprises a binding material, and wherein the second phase material comprises a high thermal conductivity particulate material (HTCPM).
In the method of packaging a high-power electronic device using a thermally conductive submount, a metal frame with diamond heat spreader, eutectic metal contacts, and high-power device attachment, the first thermally conductive bonding material (TCBM) layer, which is applied to the submount, is made of two parts: a first phase material and a second phase material. The first phase acts as a binding material, holding everything together. The second phase consists of high thermal conductivity particulate material (HTCPM) to improve heat transfer.
12. The method of claim 11 , wherein the binding material comprises at least one of parylene, benzocyclobutene, polyimide, sylgard, silicone, and combinations thereof, and wherein the HTCPM comprises at least one of particulate diamond, AlN, BeO, and combinations thereof.
Within the high-power electronic device packaging method using a thermally conductive submount, metal frame, diamond heat spreader, eutectic metal contacts, high-power device attachment, and a first thermally conductive bonding material (TCBM) layer consisting of a binding material and high thermal conductivity particulate material (HTCPM); the binding material can be parylene, benzocyclobutene, polyimide, sylgard, or silicone. The HTCPM can be particulate diamond, AlN, BeO, or a combination of these, improving heat dissipation.
13. The method of claim 1 , wherein the thermally conductive submount comprises at least one of CuW, CuMoCu, Cu/Mo/Cu, Cu/CuMo/Cu, alumina, Cu/Mo/Cu multilayers, and Al-diamond/Ag-diamond.
In the method of packaging a high-power electronic device using a metal frame, a diamond head, eutectic metal contacts, and high-power device attachment, the thermally conductive submount may be comprised of CuW, CuMoCu, Cu/Mo/Cu, Cu/CuMo/Cu, alumina, Cu/Mo/Cu multilayers, or Al-diamond/Ag-diamond. This lists suitable materials for the submount, which helps conduct heat away from the electronic device.
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August 17, 2015
March 21, 2017
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